1. Field of the Invention
The present invention generally relates to aircraft-delivered ordnance and, more particularly, is concerned with a system for wire-free arming of an aircraft-delivered bomb.
2. Description of the Prior Art
The arming of aircraft-delivered ordnance, or bombs, has remained essentially unchanged since its inception in World War II. Basically, arming occurs when an arming wire attached between the aircraft bomb rack and the bomb, pulls a pin from a fuze which will then allow the fuze to arm. The arming wire may also at the same time or separately actuate a mechanism that fires a thermal battery or a mechanism that allows ordnance fins to be deployed. Multiple arming wires may be used to perform the various arming tasks necessary for some present day weapons. Thus, the arming process may be quite complicated.
Typically, the arming wire is attached to the aircraft at the bomb rack. There are several termination points that can be used depending on the actuation force and purpose. One point that can be used is an attachment lug (referred to as a positive arming lug) that will result in the arming wire, or lanyard, always being pulled when the bomb drops away from the rack. Another attachment point is the arming solenoid which allows the pilot to select whether or not the arming wire will be pulled when the bomb drops.
On a typical bomb rack there are three attachment points that can be used for positive arming of the arming wire whereby the wire will always get pulled. Additionally, there are two arming solenoids, located fore and aft, which can be independently selected to release or hold the arming wire. More than one arming wire can be attached to the positive arming lugs but only one wire is terminated by the arming solenoid.
The above-described present method of arming aircraft-delivered ordnance by use of an arming wire connecting the bomb to the aircraft bomb rack has several deficiencies in terms of both reliability and safety. One deficiency is that the arming wire may not be installed correctly so that when the weapon is released, the arming wire does not pull the pin from the fuze. As ordnance becomes more complicated to arm, this deficiency becomes more critical. In several current weapons, for instance, there are three separate arming wires that arm the rocket motor, thermal battery, and tail fuze.
Another deficiency is that material defects in the arming wire or in the ordnance interface to the arming wire may cause the wire to fail before arming occurs. Still another deficiency is that bird strikes or other foreign object collisions may cause arming unintentionally or may break the arming wire, preventing arming from occurring.
A further deficiency is that ordnance may become armed unintentionally. One instance where this can happen is when the bomb release lugs do not completely release the bomb on ejection. Typically when a bomb "hangs up", one lug releases properly but the other lug does not. When this happens, the movement of the bomb itself causes the arming wire to be pulled and thus arm itself. Another instance where unintentional arming of the bomb by the arming wire can occur is when the bomb is accidentally dropped at zero airspeed, such as on an aircraft carrier deck. Still another instance is a midair collision between aircraft which results in pulling of the arming wire and unintentional arming of the bomb. A further instance is an ordnance jettison situation where the pilot desires to drop the bomb without arming it. The arming solenoid does not always release the arming wire. Thus, bombs that are intended to be dropped unarmed are actually armed. As should be readily apparent, these occurrences of unintentional arming are of significant concern to pilots.
Arming wires also are relatively inflexible in communicating arming information to the fuze. Conventional methods of communicating information to the fuze use the two arming wire solenoids on the bomb rack. One solenoid is used to arm or not arm the fuze. The other solenoid is used to open or not open retard fins when used or for tail fuze arming or other uses depending on the bomb involved. In any case, however, there are only two conditions that can be communicated: the arm/no arm condition and a second optional condition.
In view of the many above-described deficiencies arising from currently used arming wires, there is a long-felt need for an alternative approach to arming of aircraft-delivered bombs which will eliminate or avoid these deficiencies.